The exemplary embodiment relates to printing devices and and more particularly to printing devices that can print on print media of different weights.
Printing devices, such as printers, copiers, and multifunction devices including them, render images on sheets of print media. The print media, which is generally paper, but can be another flexible substrate, is fed from a media supply component along a paper path that carries the sheets to a marking component, which renders the images on the sheets using a marking medium, such as inks, toners, or the like. The media supply component may include one or more paper trays. The print media installed in the trays may be of different sizes, thicknesses, and weights (expressed as basis weights or wt/unit area). The basis weight of a sheet of paper is generally expressed in terms of the weight (e.g., in pounds) of a ream (500 sheets) of that paper. The wt/unit area of a sheet is usually expressed in grams/m2 (gsm or grammage).
The weight of the paper influences the settings used by the printer, e.g., for operating the paper path and the marking component. The paper weight is often manually entered by the user, and thus is prone to error.
Various methods have been developed for automatic detection of paper properties. Vacuum systems have been developed for measuring bending stiffness, as disclosed, for example, in U.S. Pub. Nos. 20030126931, 20030200815, 20030205093, and 20040217539 to Clarke. It is also known to have in-line sensors which detect sheet thickness through displacement of a nip idler roller as disclosed, for example, in U.S. Pub. No. 20050280205 to Knierim. A sheet beam strength sensor, which measures a beam strength and curl characteristics signature profile, is disclosed, for example, in U.S. Pat. No. 9,604,478 to Montfort, et al. A basis weight sensor using an infrared emitter and a phototransistor receptor are described in U.S. Pat. No. 5,138,178 to Wong, et al.